The invention relates to a brake force distributor, particularly for road vehicles, for connection with the hydraulic brake line leading from the master cylinder to the wheel brake cylinders, said brake force distributor being used to obtain a brake pressure control corresponding with the dynamic shift of the axle load.
Due to the shift of the axle load during the braking operation, the wheels of the rear axle of a vehicle tend to be overbraked and lock with increasing deceleration. This can be prevented by a brake force distributor which throttles or cuts off the flow of hydraulic brake fluid to the wheel brake cylinders of the rear axle when the load on that axle is reduced due to deceleration.
In the German periodical "AUTOMOBILTECHNISCHE ZEITSCHRIFT" No. 8/1964 an axle-load dependent controlled brake force distributor is described consisting of a hydraulic part and a mechanical part. The housing pertaining to the hydraulic part -- the latter acting as a pressure-reducing valve -- receives a double-stepped piston having a cone valve along its longitudinal axis which is open in rest position. The mechanical part consists of a prestressed spring which determines the point of response of the pressure-reducing valve, the spring seating at one end against the piston of the pressure-reducing valve while the other end seats against a mechanism for changing the preload on the spring.
The relatively large overall length of this brake force distributor is disadvantageous. In addition, the manufacturing and spring tolerances require that an adjusting screw be provided for the adjustment of the brake force distributor after the hydraulic portion has been screwed together with the mechanical portion. This of course is a disadvantage with regards to the manufacturing and assembly costs.
It is known in the art that the housing of the hydraulic part and the mechanical part could be connected together by crimping techniques. However, employment of such a technique results in material flow and, thus, a change in length of the members being connected together. Therefore, if the control spring had applied thereto a force sufficient to achieve the proper prestress for determining the point of response of the pressure-reducing valve prior to crimping, this prestress would be altered by the crimping technique due to the material flow. Thus, it would still be necessary to provide an adjusting screw for the control spring to achieve the proper prestress after the crimped connection is made.